21118872 has 16 divisors (see below), whose sum is σ = 52797240. Its totient is φ = 7039616.

The previous prime is 21118849. The next prime is 21118883. The reversal of 21118872 is 27881112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 439953 + ... + 440000.

Almost surely, 2^21118872 is an apocalyptic number.

It is an amenable number.

21118872 is an abundant number, since it is smaller than the sum of its proper divisors (31678368).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21118872 is a wasteful number, since it uses less digits than its factorization.

21118872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 879962 (or 879958 counting only the distinct ones).

The product of its digits is 1792, while the sum is 30.

The square root of 21118872 is about 4595.5273908443. The cubic root of 21118872 is about 276.4120080539.

Adding to 21118872 its reverse (27881112), we get a palindrome (48999984).

The spelling of 21118872 in words is "twenty-one million, one hundred eighteen thousand, eight hundred seventy-two".